xušé bandi-ye pâygâni
Fr.: groupement hiérarchique
A model in which a system of self-gravitating particles will gradually aggregate into larger and larger gravitationally bound groups and clusters.
Fr.: cosmologie hiérarchique
A cosmology characterized by clustering of galaxy clusters in increasingly larger systems.
hierarchical multiple system
râžmân-e bastâyi-ye pâygâni
Fr.: système multiple hiérarchique
A → multiple star system in which the stars can be divided into two groups, each of which traverses a larger orbit around the system's center of mass. Each of these smaller groups must also be hierarchical, which means that they must be divided into smaller subgroups which themselves are hierarchical, and so on. Hierarchical multiple systems have long-term dynamical stability.
hierarchical structure formation
diseš-e sâxtâr-e pâygâni
Fr.: formation de structures hiérarchiques
A cosmological → structure formation model in which the smallest gravitationally bound structures (→ quasars and galaxies) form first, followed by → groups, → galaxy clusters, and → superclusters of galaxies.
hierarchical triple system
râžmân-e bastâyi-ye nâpâygâni
Fr.: système multiple non hiérarchique
A triple star system in which the (inner) binary is orbited by a third body in a much wider orbit. → hierarchical multiple system.
A system in which the components are organized in increasingly larger structures.
From O.Fr. ierarchie, from M.L. hierarchia "ranked division of angels," from Gk. hierarchia "rule of a high priest," from hierarches "high priest, leader of sacred rites," from ta hiera "the sacred rites" (neut. pl. of hieros "sacred") + archein "to lead, rule."
Pâygân, from pâyé "step, rank, degree," from pây, pâ "foot, step," from Mid.Pers. pâd, pây; Av. pad- "foot" (cf. Skt. pat; Gk. pos, gen. podos; L. pes, gen. pedis; P.Gmc. *fot; E. foot; Ger. Fuss; Fr. pied; PIE *pod-/*ped-) + -gân suffix forming plural entities, from Mid.Pers. -gânag, -gâna, from Proto-Iranian *kāna-ka-.
Hindu-Arabic numeral system
râžmân-e adadhâ-ye Hendi-Arabi
Fr.: numération indo-arabe
Same as → Indian numeral system.
Fr.: opérateur d'identité
An operator which takes a real number to the same real number.
Fr.: température d'inflammation
The minimum temperature to which a fuel must be heated in order to initiate self sustained combustion independent of another heat source.
Fr.: inperare (L.)
Latin verb meaning "to command, rule, reign."
L. imperare "to command, give orders, exercise authority," from → in- "into, in" + parare "to make ready, supply, order," related to parire "produce, give birth to," from PIE root *pere- "to produce, procure;" cf. Skt. prthukah "child, calf, young of an animal;" Gk. poris "calf, bull;" Czech spratek "brat, premature calf;" Lith. periu, pereti "to brood;" O.H.G. farro, Ger. Farre, Du. varre "bull," O.E. fearr "bull;" see below for possible Iranian cognates.
Parmâtidan, from BMP plm'(d)y "to command, order," Sogd. framat- "to command," variants of farmudan, farmâyidan "to command, to order," ultimately from prefixed Proto-Ir. *fra-maH-, from *maH- "to measure," → experiment.
1) parmâte; 2) parmâti
Fr.: 1) inpératif; 2) impériux
1a) A command or order.
From L.L. imperativus "pertaining to a command," from imperat-, p.p. stem of → imperare "to command."
Parmât, noun from present stem of parmâtidan, → imperare; parmâtii, adj. from parmât.
kâte-ye parmâti, ~ farmâni
Fr.: cas impératif
The grammatical mood of a verb that expresses a command or a request, as in close the door!.
In an imperative manner.
Indian numeral system
râžmân-e adahâ-ye Hendi
Fr.: numération indienne
The → numeral system consisting of the numerals 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 which evolved into the system we use today. The Indian numerals was a place-value or positional system. The Indians were the first to develop a base 10 positional system. Same as → Hindu-Arabic numeral system.
Fr.: caméra infrarouge
Fr.: accélération instantanée
The → acceleration of a particle at time t defined by a = lim Δv/Δt = dv/dt. It is the limiting value of Δv/Δt at time t as both Δv and Δt approach zero.
Fr.: opérateur intégral
Math.: An operator whose inverse is a differential operator.
To act upon one another; have a mutual or reciprocal action.
Fr.: binaire en interaction
Fr.: galaxies en interaction
Galaxies that are close enough for their mutual gravitational attraction to produce perturbed shapes or extruded filaments of stellar material, called → tidal tails. Most galaxies are in clusters, and gravitational interactions between them are common.